The article, which retrospectively covers the publication of sources of the 18th century in Lithuania in the period from the 1910s to present, aims at highlighting the main groups of published sources and discussing problems faced by publishers of texts in other languages. The first half of the 20th century should be considered the beginning of the publication of sources referring to the 18th century. In the said period, the focus lay on sources in the Lithuanian language. Systematic issuing of sources of the 18th century drawn up in other languages (Latin, Ruthenian, Polish and German) was initiated only in the 1950s. Most sources of the 18th century appeared in serial publications. Objectives set by each series of sources reflected on the selection of external sources for publication and the mode of their preparation for printing (facsimile edition, publication in the original language, publication of translation, etc.). In the Soviet times series of source publications were mostly based on the inter-institutional principle and were organized around a certain publishing house, however, the restoration of Lithuania’s independence, the major publication works have been pursued in academic institutes. Publication of sources reflects the mission and strategic objectives of a certain academic institution. Universities, however, play only a minor role in source publication. Documents and other narrative sources have hitherto been prepared for publication with no obligation to comply with certain unanimous system of source preparation or unified principles of their publication. Neither obligatory nor recommendatory instructions for the preparation for publication of a source in another language have been offered. Both – different historiographical schools, their attitude and traditions, character of published sources and the fact that sources are prepared and published by representatives of different fields of science (philology, history, philosophy, art criticism, musicology) with individual approach to the value produced by the source and at times little willingness to cooperate, are accountable for the situation. In each situation different principles of source publication apply which, subject to the nature of the source, requirements posed to the publication and attitude of the editor, can vary even when publishing books in one series. Analysis of published sources allows for the distinguishing of three main trends in the preparation of texts of the 18th century in the Polish language: 1) graphic representation of the authentic source; 2) modernization of the published texts through “correction” of “mistakes”, usage of upper and lower case letters in accordance with the rules of orthography of the contemporary Polish language and introduction of punctuation marks to facilitate the understanding of at times particularly lengthy sentences of the published text, etc.; 3) opting for the “golden mean” with a view to combine both methods of text representation. All these modes of publishing have certain advantages and disadvantages. The most urgent problem is “modernization” of the text when speaking about the preparation for publication of written records made in the Lithuanian territories of the Grand Duchy of Lithuania. It is obvious that the time has come to make a decision with regard to the drafting of new publication principles to a greater extent adapted to the Lithuanian contexts, designed to preserve the specificity of texts created in Lithuania and facilitate the analysis of the relics of the Lithuanian language preserved in Polish writings.